Hydrostatic Pressure Simulation Issue

[Anonymous]

Hello,

I am trying to use the hydrostatic pressure function to simulate water in a simple 1m square container with 6mm wall thickness and an open top.

I modelled the container, moved to simulation and did the following.

1. Set the study material to polyethylene, low density
2. Set the bottom external face of the container as a fixed structural constraint
3. Added structural load, changed type to hydro static which enabled gravity.
4. I selected the four internal faces of the container.
5. I selected point coordinate and set y to 500mm i.e. half the height of the container.
6. I left fluid as water and hit okay. 

I then solved the model and the results don't make sense to me for example the max displacement is at the open end despite me setting the water level to only 50% of the container. Also some walls deform out which I would expect but some deform in and the corners of the container aren't deforming. I would have expected to see the walls bulge low down on the container but maybe I'm mistaken.

Anyone know what I've done wrong here?

Thanks in advance

[TheCADWhisperer]

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

[Anonymous]

The file should be attached, thanks

[James.Youmatz · Accepted solution]

Hi @Anonymous,

Welcome to the Fusion 360 Community!

Edit: Just found the difference - you are using structural buckling where I used linear static stress. I don't believe that buckling would be the correct analysis type for what you are looking for. In this situation - nothing is really in compression so I couldn't imagine the walls buckling. I believe the results you are seeing is the shape that the model would be if it were to buckle. 

I just recreated this from scratch and seemed to get results that make sense. Only a few things I can think of that might be different - our mesh settings or where we placed the the point coordinate (mine was 500,500,500 in XYZ respectively). Check out my attached file below.

Thanks,

[Anonymous]

Thanks James, I taught the hydrostatic pressure load was only in the structural buckling study type for some reason. Just tried the static stress type with a cylindrical container I had previously tried with no success and it looks deform as I would expect now.

Thanks again, I should have asked sooner and saved myself a lot of head scratching 🙂